This review assessed 1-year vertebral fracture risk reduction in treatments for osteoporosis. The author concluded that risedronate reduced the risk of fractures and that post hoc analyses have shown alendronate and raloxifene to be effective. These conclusions were, in part, based upon an inappropriate interpretation of the results and, therefore, are likely to be unreliable.

MEDLINE was searched from 1990 onwards, and the bibliographies of selected citations and recent meeting abstracts were checked for studies reported in English.

Study selection

Study designs of evaluations included in the review

Randomised controlled trials (RCTs) were eligible for inclusion. However, one meta-analysis and 7 retrospective post hoc analyses were also included.

Specific interventions included in the review

Studies that assessed any medication currently approved for the treatment of osteoporosis were eligible for inclusion. The drugs assessed in the review were risedronate, raloxifene and alendronate versus placebo. The participants also received calcium and vitamin D supplements where indicated.

Participants included in the review

Adults with postmenopausal osteoporosis, or those at risk for or experiencing glucocorticoid-induced osteoporosis, were included. In the studies conducted in postmenopausal women, most had established oestoporosis defined as prevalent vertebral fracture at baseline and/or had a T-score of less than or equal to 2.0 at one of the skeletal sites tested. In the studies conducted in participants receiving long-term glucocorticoids, most had received therapy for one year.

Outcomes assessed in the review

How were decisions on the relevance of primary studies made?

The author did not state how the papers were selected for the review, or how many reviewers performed the selection.

Assessment of study quality

Study quality was assessed according to a checklist (see Other Publications of Related Interest): level A represented high-quality RCTs or meta-analyses; level B represented other evidence, including well-designed, non-randomised clinical trials (CCTs) and low-quality RCTs, including post hoc subgroup analyses or data presented in abstract form; level C represented consensus or expert opinion. The author assessed the papers according to the criteria in the checklist, but did not state how many reviewers performed the quality assessment.

Data extraction

The author did not state how the data were extracted for the review, or how many reviewers performed the data extraction. Data were extracted on the type of analysis undertaken, baseline patient characteristics, intervention, method of vertebral fracture assessment, and fracture data (incidence, relative risk reduction or absolute risk reduction). The corresponding number-needed-to-treat was calculated for each study.

Methods of synthesis

How were the studies combined?

The studies were combined in a narrative discussion grouped according to the drug type and patient population (postmenopausal osteoporosis and glucocorticoid-induced osteoporosis).

How were differences between studies investigated?

Differences between the studies were not discussed.

Results of the review

Ten different studies, reported in 13 references, were included. These were one meta-analysis, 5 RCTs (total n=4,675) and 7 post hoc subgroup analyses, either of the RCTs included in the review or other further RCTs.

In prospective analyses, the 1-year risk of new morphometric vertebral fractures was significantly reduced by risedronate (5 mg/day) in two 3-year studies in postmenopausal women with vertebral fractures compared with placebo. In a further two prospective analyses that also assessed risedronate versus placebo in patients either at risk of, or who had glucocorticoid-induced osteoporosis, no significant differences were observed between the groups.

In post hoc analyses, the 1-year risk of vertebral fractures was significantly reduced by alendronate and raloxifene in participants with postmenopausal vertebral fractures. No significant benefit was observed for treatment with alendronate in participants with glucocorticoid-induced osteoporosis.

Authors' conclusions

Risedronate has been shown to rapidly reduce the risk of new vertebral fractures within 1 year of treatment in both postmenopausal and glucocorticoid-induced osteoporosis. In addition, in post hoc analyses, alendronate and raloxifene have been shown to reduce the incidence of clinical vertebral fractures within 1 year of therapy.

CRD commentary

This was a poorly defined and conducted review. The review question was reasonably clear, but the inclusion criteria were not adhered to. Two sources were searched from 1990 onwards for relevant papers published in English. No attempts were made to minimise language or publication bias. The methods used to select the studies, assess study quality and extract the data were not described; it is therefore unclear whether any efforts were made to minimise bias and errors. In addition, the checklist used to assess study quality was inadequate.

Some details of the included studies were tabulated, but there were discrepancies between some of the results reported and those in the text. Since the inclusion criteria were not adhered to, several different study designs that included retrospective analyses of trial data that were also reported prospectively were included. In some of the trials, the results were conflicting between the different analyses, and in some instances these were interpreted and emphasised inappropriately. The author's conclusions are, in part, based upon this inappropriate emphasis and, therefore, are likely to be unreliable.

Implications of the review for practice and research

The author did not state any implications for practice or further research.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.